Two-dimensional materials for aqueous zinc-ion batteries

Aqueous zinc-ion batteries (ZIBs) are considered as a promising energy storage system for large-scale energy storage in terms of their high safety and low cost. In recent years, two-dimensional (2D) materials have been widely applied in designing the electrodes of aqueous ZIBs since they generally possess the characteristics of large surface areas, plentiful ion transport channels and abundant active sites. Thus, they can not only act as the active materials and conductive additives in cathodes, but also be employed as the artificial interface layers or conductive substrates of Zn anodes. In this review, the issues of aqueous ZIBs and the unique properties of 2D materials are discussed briefly. Then we highlight the recent advances of the applications of various 2D materials, mainly including transition metal oxides, transition metal dichalcogenide, graphene and MXenes, in the design of the cathodes and anodes of aqueous ZIBs. Finally, we present the challenges and perspectives of 2D materials in aqueous ZIBs.